The present invention relates generally to aircraft gas turbine engines, and, more specifically, to thrust reversers therefor.
In a turbofan engine, combustion gases are discharged through an exhaust nozzle for providing thrust to propel an aircraft in flight. Upon landing, a thrust reverser is deployed for reversing the direction of exhaust flow for providing a braking thrust force for reducing aircraft ground speed.
A common thrust reverser includes a pair of thrust reverser doors which surround the exhaust nozzle on diametrically opposite sides thereof when stowed or retracted. In this position, the trailing edges or lips of the doors surround the nozzle outlet and provide unobstructed flow therefrom.
The doors are deployed by rotation or pivoting thereof, with the aft lips moving radially inwardly to block the nozzle outlet, and leading edges or lips moved radially outwardly to uncover side outlets of the nozzle. The deployed doors have a clamshell configuration which redirects the exhaust flow radially outwardly through the sides of the nozzle and in an axially forward direction for providing reverse thrust.
In a typical configuration, the individual doors are mounted to the exhaust nozzle at single pivots. The doors may thusly be simply opened and closed by single axis pivoting using a suitable actuator.
However, the doors must be securely locked when stowed to prevent inadvertent deployment during flight. Door locking must be effected with a high level of reliability, which correspondingly substantially increases the complexity, weight, and expense of the thrust reverser. Increased complexity of the thrust reverser increases cost of initial procurement as well as maintenance thereof over its useful life. Increased complexity adds weight to the thrust reverser and correspondingly reduces overall performance of the aircraft.
The Federal Aviation Administration (FAA) has requirements for further increasing thrust reverser reliability. Increased reliability requirements cause a further increase in complexity of conventional single pivot thrust reversers, and further increase cost, weight, and maintenance requirements therefor.
Accordingly, it is desired to provide an improved thrust reverser having increased reliability without corresponding increase in complexity thereof.